Conventional fire hydrants offer access to a municipal water supply in a manner in which operatives with ill intent may appreciate. Briefly, conventional fire hydrants include at least one nozzle for coupling to a fire hose. A threaded cap closes off the nozzle when the hydrant is not in use. The hydrant also includes a hydrant valve which controls flow of water from the water supply to and through the hydrant, through the nozzle, and into the fire hose.
Conventionally, the barrel of the hydrant between the nozzle and the hydrant valve, which is in the lower portion of the hydrant, accommodates several gallons of fluid. Accordingly, it is possible to unscrew a nozzle cap, introduce gallons of toxin, reattach the nozzle cap and open the hydrant valve to allow the toxins to communicate with and flow by gravity and perhaps at least to some extent by Bernoulli's principle, into the municipal water supply, since when the nozzle cap is attached, water pressure from the water supply would not force the toxins back out of the hydrant.
Accordingly, in U.S. patent application Ser. No. 11/265,051, entitled “Fire Hydrant With Second Valve,” which is a continuation-in-part of U.S. patent application Ser. No. 10/309,646, entitled “Fire Hydrant With Second Valve,” the entire contents of each of which are hereby incorporated by this reference, a seat is affixed to the interior cavity of the fire hydrant using an adhesive or mechanical means, a valve structure is introduced between the nozzle and the hydrant valve and cooperates with the seat to make it more difficult or impossible to introduce toxins to a water supply through a fire hydrant. The valve structure prevents or substantially prevents the flow of water through the valve and thus closes off portions of the hydrant barrel when a nozzle is open but the hydrant valve is closed. Generally, the valve structure comprises a secondary valve, a seat, and biasing structure.
Retrofitting fire hydrants with a secondary valves may be accomplished by removing the hydrant barrel, inserting the secondary valve and affixing the seat to the hydrant body with an adhesive or mechanical means, such as a screw. While this is an effective method for installing the secondary valve, another less expensive and more efficient method is needed to retrofit a fire hydrant with the secondary valve.